Checking Compression Pressure
- Before checking compression, check the engine oil level and that the starter motor and battery are all in normal operating condition.
- Start the engine and wait until engine coolant temperature has risen to 80-95°C
- Stop the engine and disconnect the spark plug cables.
- Remove the spark plugs.
- Turn over the engine to remove any foreign objects in the cylinders.
- Attach the compression gauge to the spark plug hole.
- Depress the accelerator pedal to fully open the throttle valve.
- Turn over the engine and read the gauge.
Standard value: 1,200 kPa (12.2 kg.cm2 , 170 psi)
Limit: 1,050 kPa (10.7 kg.cm2 , 149 psi)
- Repeat steps 6 through 8 on all cylinders, making sure ensuring that the pressure difference for each of the cylinders is within the specified limit.
Limit: Max 100 kPa (1.0 kg/cm2 , 14 psi) for all cylinders.
- If a cylinder's compression or pressure difference is below the specification, add a small amount of oil through the spark plug hole and repeat steps 6 through 9.
- If the addition of oil causes the compression to rise, it is possible that there is wear between the piston ring and cylinder wall.
- If the compression doesn't rise, valve seizure, poor valve seating or a compression leak from the cylinder head gasket are all possible causes.
Spark plug tightening torque: 20-30 N.m (200 - 300 kg.cm, 14.75 - 22.13 lb.ft.)